1. Field of the Invention
The present invention is related to managing data storage space. In particular, the present invention is related to managing quotas for users of a data storage system.
2. Description of the Related Art
As users and entities use more and more data, data storage space becomes more scarce. Many data storage systems designed for use by multiple users implement quotas. Each user is allocated a certain amount of data space, as a quota, to use on the data storage systems.
Many data storage systems implement offline or backup storage. When data on primary or hard disk is not high priority, the data may be migrated to backup storage. This helps keep high priority data accessible with quicker access times, such as from hard drives, and keeps lower priority data on slower access systems, such as tape devices.
In data storage systems shared among many users, the quotas are managed for the hard disks. Thus, if a user moves data from hard disk space to offline backup space, the user may reduce the data counted against his quota though may still be using storage space in the offline storage. This can be costly for data storage system providers, as users may utilize more data than they are paying for.
What is needed is an improved method for tracking quotas in modern day storage systems having multiple tiers.